Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

DBIx::Class::ResultSource(3)         User Contributed Perl Documentation        DBIx::Class::ResultSource(3)



NAME
       DBIx::Class::ResultSource - Result source object

SYNOPSIS
         # Create a table based result source, in a result class.

         package MyApp::Schema::Result::Artist;
         use base qw/DBIx::Class::Core/;

         __PACKAGE__->table('artist');
         __PACKAGE__->add_columns(qw/ artistid name /);
         __PACKAGE__->set_primary_key('artistid');
         __PACKAGE__->has_many(cds => 'MyApp::Schema::Result::CD');

         1;

         # Create a query (view) based result source, in a result class
         package MyApp::Schema::Result::Year2000CDs;
         use base qw/DBIx::Class::Core/;

         __PACKAGE__->load_components('InflateColumn::DateTime');
         __PACKAGE__->table_class('DBIx::Class::ResultSource::View');

         __PACKAGE__->table('year2000cds');
         __PACKAGE__->result_source_instance->is_virtual(1);
         __PACKAGE__->result_source_instance->view_definition(
             "SELECT cdid, artist, title FROM cd WHERE year ='2000'"
             );

DESCRIPTION
       A ResultSource is an object that represents a source of data for querying.

       This class is a base class for various specialised types of result sources, for example
       DBIx::Class::ResultSource::Table. Table is the default result source type, so one is created for you
       when defining a result class as described in the synopsis above.

       More specifically, the DBIx::Class::Core base class pulls in the
       DBIx::Class::ResultSourceProxy::Table component, which defines the table method.  When called,
       "table" creates and stores an instance of DBIx::Class::ResultSoure::Table. Luckily, to use tables as
       result sources, you don't need to remember any of this.

       Result sources representing select queries, or views, can also be created, see
       DBIx::Class::ResultSource::View for full details.

   Finding result source objects
       As mentioned above, a result source instance is created and stored for you when you define a Result
       Class.

       You can retrieve the result source at runtime in the following ways:

       From a Schema object:
              $schema->source($source_name);

       From a Row object:
              $row->result_source;

       From a ResultSet object:
              $rs->result_source;

METHODS
   add_columns
       Arguments: @columns
       Return value: The ResultSource object

         $source->add_columns(qw/col1 col2 col3/);

         $source->add_columns('col1' => \%col1_info, 'col2' => \%col2_info, ...);

       Adds columns to the result source. If supplied colname => hashref pairs, uses the hashref as the
       "column_info" for that column. Repeated calls of this method will add more columns, not replace them.

       The column names given will be created as accessor methods on your DBIx::Class::Row objects. You can
       change the name of the accessor by supplying an "accessor" in the column_info hash.

       If a column name beginning with a plus sign ('+col1') is provided, the attributes provided will be
       merged with any existing attributes for the column, with the new attributes taking precedence in the
       case that an attribute already exists. Using this without a hashref ("$source->add_columns(qw/+col1
       +col2/)") is legal, but useless -- it does the same thing it would do without the plus.

       The contents of the column_info are not set in stone. The following keys are currently
       recognised/used by DBIx::Class:

       accessor
              { accessor => '_name' }

              # example use, replace standard accessor with one of your own:
              sub name {
                  my ($self, $value) = @_;

                  die "Name cannot contain digits!" if($value =~ /\d/);
                  $self->_name($value);

                  return $self->_name();
              }

           Use this to set the name of the accessor method for this column. If unset, the name of the column
           will be used.

       data_type
              { data_type => 'integer' }

           This contains the column type. It is automatically filled if you use the
           SQL::Translator::Producer::DBIx::Class::File producer, or the DBIx::Class::Schema::Loader module.

           Currently there is no standard set of values for the data_type. Use whatever your database
           supports.

       size
              { size => 20 }

           The length of your column, if it is a column type that can have a size restriction. This is
           currently only used to create tables from your schema, see "deploy" in DBIx::Class::Schema.

       is_nullable
              { is_nullable => 1 }

           Set this to a true value for a columns that is allowed to contain NULL values, default is false.
           This is currently only used to create tables from your schema, see "deploy" in
           DBIx::Class::Schema.

       is_auto_increment
              { is_auto_increment => 1 }

           Set this to a true value for a column whose value is somehow automatically set, defaults to
           false. This is used to determine which columns to empty when cloning objects using "copy" in
           DBIx::Class::Row. It is also used by "deploy" in DBIx::Class::Schema.

       is_numeric
              { is_numeric => 1 }

           Set this to a true or false value (not "undef") to explicitly specify if this column contains
           numeric data. This controls how set_column decides whether to consider a column dirty after an
           update: if "is_numeric" is true a numeric comparison "!=" will take place instead of the usual
           "eq"

           If not specified the storage class will attempt to figure this out on first access to the column,
           based on the column "data_type". The result will be cached in this attribute.

       is_foreign_key
              { is_foreign_key => 1 }

           Set this to a true value for a column that contains a key from a foreign table, defaults to
           false. This is currently only used to create tables from your schema, see "deploy" in
           DBIx::Class::Schema.

       default_value
              { default_value => \'now()' }

           Set this to the default value which will be inserted into a column by the database. Can contain
           either a value or a function (use a reference to a scalar e.g. "\'now()'" if you want a
           function). This is currently only used to create tables from your schema, see "deploy" in
           DBIx::Class::Schema.

           See the note on "new" in DBIx::Class::Row for more information about possible issues related to
           db-side default values.

       sequence
              { sequence => 'my_table_seq' }

           Set this on a primary key column to the name of the sequence used to generate a new key value. If
           not specified, DBIx::Class::PK::Auto will attempt to retrieve the name of the sequence from the
           database automatically.

       retrieve_on_insert
             { retrieve_on_insert => 1 }

           For every column where this is set to true, DBIC will retrieve the RDBMS-side value upon a new
           row insertion (normally only the autoincrement PK is retrieved on insert). "INSERT ... RETURNING"
           is used automatically if supported by the underlying storage, otherwise an extra SELECT statement
           is executed to retrieve the missing data.

       auto_nextval
              { auto_nextval => 1 }

           Set this to a true value for a column whose value is retrieved automatically from a sequence or
           function (if supported by your Storage driver.) For a sequence, if you do not use a trigger to
           get the nextval, you have to set the "sequence" value as well.

           Also set this for MSSQL columns with the 'uniqueidentifier' data_type whose values you want to
           automatically generate using "NEWID()", unless they are a primary key in which case this will be
           done anyway.

       extra
           This is used by "deploy" in DBIx::Class::Schema and SQL::Translator to add extra non-generic data
           to the column. For example: "extra => { unsigned => 1}" is used by the MySQL producer to set an
           integer column to unsigned. For more details, see SQL::Translator::Producer::MySQL.

   add_column
       Arguments: $colname, \%columninfo?
       Return value: 1/0 (true/false)

         $source->add_column('col' => \%info);

       Add a single column and optional column info. Uses the same column info keys as "add_columns".

   has_column
       Arguments: $colname
       Return value: 1/0 (true/false)

         if ($source->has_column($colname)) { ... }

       Returns true if the source has a column of this name, false otherwise.

   column_info
       Arguments: $colname
       Return value: Hashref of info

         my $info = $source->column_info($col);

       Returns the column metadata hashref for a column, as originally passed to "add_columns". See
       "add_columns" above for information on the contents of the hashref.

   columns
       Arguments: None
       Return value: Ordered list of column names

         my @column_names = $source->columns;

       Returns all column names in the order they were declared to "add_columns".

   columns_info
       Arguments: \@colnames ?
       Return value: Hashref of column name/info pairs

         my $columns_info = $source->columns_info;

       Like "column_info" but returns information for the requested columns. If the optional column-list
       arrayref is omitted it returns info on all columns currently defined on the ResultSource via
       "add_columns".

   remove_columns
       Arguments: @colnames
       Return value: undefined

         $source->remove_columns(qw/col1 col2 col3/);

       Removes the given list of columns by name, from the result source.

       Warning: Removing a column that is also used in the sources primary key, or in one of the sources
       unique constraints, will result in a broken result source.

   remove_column
       Arguments: $colname
       Return value: undefined

         $source->remove_column('col');

       Remove a single column by name from the result source, similar to "remove_columns".

       Warning: Removing a column that is also used in the sources primary key, or in one of the sources
       unique constraints, will result in a broken result source.

   set_primary_key
       Arguments: @cols
       Return value: undefined

       Defines one or more columns as primary key for this source. Must be called after "add_columns".

       Additionally, defines a unique constraint named "primary".

       Note: you normally do want to define a primary key on your sources even if the underlying database
       table does not have a primary key.  See "The Significance and Importance of Primary Keys" in
       DBIx::Class::Manual::Intro for more info.

   primary_columns
       Arguments: None
       Return value: Ordered list of primary column names

       Read-only accessor which returns the list of primary keys, supplied by "set_primary_key".

   sequence
       Manually define the correct sequence for your table, to avoid the overhead associated with looking up
       the sequence automatically. The supplied sequence will be applied to the "column_info" of each
       primary_key

       Arguments: $sequence_name
       Return value: undefined

   add_unique_constraint
       Arguments: $name?, \@colnames
       Return value: undefined

       Declare a unique constraint on this source. Call once for each unique constraint.

         # For UNIQUE (column1, column2)
         __PACKAGE__->add_unique_constraint(
           constraint_name => [ qw/column1 column2/ ],
         );

       Alternatively, you can specify only the columns:

         __PACKAGE__->add_unique_constraint([ qw/column1 column2/ ]);

       This will result in a unique constraint named "table_column1_column2", where "table" is replaced with
       the table name.

       Unique constraints are used, for example, when you pass the constraint name as the "key" attribute to
       "find" in DBIx::Class::ResultSet. Then only columns in the constraint are searched.

       Throws an error if any of the given column names do not yet exist on the result source.

   add_unique_constraints
       Arguments: @constraints
       Return value: undefined

       Declare multiple unique constraints on this source.

         __PACKAGE__->add_unique_constraints(
           constraint_name1 => [ qw/column1 column2/ ],
           constraint_name2 => [ qw/column2 column3/ ],
         );

       Alternatively, you can specify only the columns:

         __PACKAGE__->add_unique_constraints(
           [ qw/column1 column2/ ],
           [ qw/column3 column4/ ]
         );

       This will result in unique constraints named "table_column1_column2" and "table_column3_column4",
       where "table" is replaced with the table name.

       Throws an error if any of the given column names do not yet exist on the result source.

       See also "add_unique_constraint".

   name_unique_constraint
       Arguments: \@colnames
       Return value: Constraint name

         $source->table('mytable');
         $source->name_unique_constraint(['col1', 'col2']);
         # returns
         'mytable_col1_col2'

       Return a name for a unique constraint containing the specified columns. The name is created by
       joining the table name and each column name, using an underscore character.

       For example, a constraint on a table named "cd" containing the columns "artist" and "title" would
       result in a constraint name of "cd_artist_title".

       This is used by "add_unique_constraint" if you do not specify the optional constraint name.

   unique_constraints
       Arguments: None
       Return value: Hash of unique constraint data

         $source->unique_constraints();

       Read-only accessor which returns a hash of unique constraints on this source.

       The hash is keyed by constraint name, and contains an arrayref of column names as values.

   unique_constraint_names
       Arguments: None
       Return value: Unique constraint names

         $source->unique_constraint_names();

       Returns the list of unique constraint names defined on this source.

   unique_constraint_columns
       Arguments: $constraintname
       Return value: List of constraint columns

         $source->unique_constraint_columns('myconstraint');

       Returns the list of columns that make up the specified unique constraint.

   sqlt_deploy_callback
       Arguments: $callback_name | \&callback_code
       Return value: $callback_name | \&callback_code

         __PACKAGE__->sqlt_deploy_callback('mycallbackmethod');

          or

         __PACKAGE__->sqlt_deploy_callback(sub {
           my ($source_instance, $sqlt_table) = @_;
           ...
         } );

       An accessor to set a callback to be called during deployment of the schema via "create_ddl_dir" in
       DBIx::Class::Schema or "deploy" in DBIx::Class::Schema.

       The callback can be set as either a code reference or the name of a method in the current result
       class.

       Defaults to "default_sqlt_deploy_hook".

       Your callback will be passed the $source object representing the ResultSource instance being
       deployed, and the SQL::Translator::Schema::Table object being created from it. The callback can be
       used to manipulate the table object or add your own customised indexes. If you need to manipulate a
       non-table object, use the "sqlt_deploy_hook" in DBIx::Class::Schema.

       See "Adding Indexes And Functions To Your SQL" in DBIx::Class::Manual::Cookbook for examples.

       This sqlt deployment callback can only be used to manipulate SQL::Translator objects as they get
       turned into SQL. To execute post-deploy statements which SQL::Translator does not currently handle,
       override "deploy" in DBIx::Class::Schema in your Schema class and call dbh_do.

   default_sqlt_deploy_hook
       This is the default deploy hook implementation which checks if your current Result class has a
       "sqlt_deploy_hook" method, and if present invokes it on the Result class directly. This is to
       preserve the semantics of "sqlt_deploy_hook" which was originally designed to expect the Result class
       name and the $sqlt_table instance of the table being deployed.

   resultset
       Arguments: None
       Return value: $resultset

       Returns a resultset for the given source. This will initially be created on demand by calling

         $self->resultset_class->new($self, $self->resultset_attributes)

       but is cached from then on unless resultset_class changes.

   resultset_class
       Arguments: $classname
       Return value: $classname

         package My::Schema::ResultSet::Artist;
         use base 'DBIx::Class::ResultSet';
         ...

         # In the result class
         __PACKAGE__->resultset_class('My::Schema::ResultSet::Artist');

         # Or in code
         $source->resultset_class('My::Schema::ResultSet::Artist');

       Set the class of the resultset. This is useful if you want to create your own resultset methods.
       Create your own class derived from DBIx::Class::ResultSet, and set it here. If called with no
       arguments, this method returns the name of the existing resultset class, if one exists.

   resultset_attributes
       Arguments: \%attrs
       Return value: \%attrs

         # In the result class
         __PACKAGE__->resultset_attributes({ order_by => [ 'id' ] });

         # Or in code
         $source->resultset_attributes({ order_by => [ 'id' ] });

       Store a collection of resultset attributes, that will be set on every DBIx::Class::ResultSet produced
       from this result source. For a full list see "ATTRIBUTES" in DBIx::Class::ResultSet.

   source_name
       Arguments: $source_name
       Result value: $source_name

       Set an alternate name for the result source when it is loaded into a schema.  This is useful if you
       want to refer to a result source by a name other than its class name.

         package ArchivedBooks;
         use base qw/DBIx::Class/;
         __PACKAGE__->table('books_archive');
         __PACKAGE__->source_name('Books');

         # from your schema...
         $schema->resultset('Books')->find(1);

   from
       Arguments: None
       Return value: FROM clause

         my $from_clause = $source->from();

       Returns an expression of the source to be supplied to storage to specify retrieval from this source.
       In the case of a database, the required FROM clause contents.

   schema
       Arguments: $schema
       Return value: A schema object

         my $schema = $source->schema();

       Sets and/or returns the DBIx::Class::Schema object to which this result source instance has been
       attached to.

   storage
       Arguments: None
       Return value: A Storage object

         $source->storage->debug(1);

       Returns the storage handle for the current schema.

       See also: DBIx::Class::Storage

   add_relationship
       Arguments: $relname, $related_source_name, \%cond, [ \%attrs ]
       Return value: 1/true if it succeeded

         $source->add_relationship('relname', 'related_source', $cond, $attrs);

       DBIx::Class::Relationship describes a series of methods which create pre-defined useful types of
       relationships. Look there first before using this method directly.

       The relationship name can be arbitrary, but must be unique for each relationship attached to this
       result source. 'related_source' should be the name with which the related result source was
       registered with the current schema. For example:

         $schema->source('Book')->add_relationship('reviews', 'Review', {
           'foreign.book_id' => 'self.id',
         });

       The condition $cond needs to be an SQL::Abstract-style representation of the join between the tables.
       For example, if you're creating a relation from Author to Book,

         { 'foreign.author_id' => 'self.id' }

       will result in the JOIN clause

         author me JOIN book foreign ON foreign.author_id = me.id

       You can specify as many foreign => self mappings as necessary.

       Valid attributes are as follows:

       join_type
           Explicitly specifies the type of join to use in the relationship. Any SQL join type is valid,
           e.g. "LEFT" or "RIGHT". It will be placed in the SQL command immediately before "JOIN".

       proxy
           An arrayref containing a list of accessors in the foreign class to proxy in the main class. If,
           for example, you do the following:

             CD->might_have(liner_notes => 'LinerNotes', undef, {
               proxy => [ qw/notes/ ],
             });

           Then, assuming LinerNotes has an accessor named notes, you can do:

             my $cd = CD->find(1);
             # set notes -- LinerNotes object is created if it doesn't exist
             $cd->notes('Notes go here');

       accessor
           Specifies the type of accessor that should be created for the relationship. Valid values are
           "single" (for when there is only a single related object), "multi" (when there can be many), and
           "filter" (for when there is a single related object, but you also want the relationship accessor
           to double as a column accessor). For "multi" accessors, an add_to_* method is also created, which
           calls "create_related" for the relationship.

       Throws an exception if the condition is improperly supplied, or cannot be resolved.

   relationships
       Arguments: None
       Return value: List of relationship names

         my @relnames = $source->relationships();

       Returns all relationship names for this source.

   relationship_info
       Arguments: $relname
       Return value: Hashref of relation data,

       Returns a hash of relationship information for the specified relationship name. The keys/values are
       as specified for "add_relationship".

   has_relationship
       Arguments: $rel
       Return value: 1/0 (true/false)

       Returns true if the source has a relationship of this name, false otherwise.

   reverse_relationship_info
       Arguments: $relname
       Return value: Hashref of relationship data

       Looks through all the relationships on the source this relationship points to, looking for one whose
       condition is the reverse of the condition on this relationship.

       A common use of this is to find the name of the "belongs_to" relation opposing a "has_many" relation.
       For definition of these look in DBIx::Class::Relationship.

       The returned hashref is keyed by the name of the opposing relationship, and contains its data in the
       same manner as "relationship_info".

   related_source
       Arguments: $relname
       Return value: $source

       Returns the result source object for the given relationship.

   related_class
       Arguments: $relname
       Return value: $classname

       Returns the class name for objects in the given relationship.

   handle
       Arguments: None
       Return value: $source_handle

       Obtain a new result source handle instance for this source. Used as a serializable pointer to this
       resultsource, as it is not easy (nor advisable) to serialize CODErefs which may very well be present
       in e.g.  relationship definitions.

   throw_exception
       See "throw_exception" in DBIx::Class::Schema.

   source_info
       Stores a hashref of per-source metadata.  No specific key names have yet been standardized, the
       examples below are purely hypothetical and don't actually accomplish anything on their own:

         __PACKAGE__->source_info({
           "_tablespace" => 'fast_disk_array_3',
           "_engine" => 'InnoDB',
         });

   new
         $class->new();

         $class->new({attribute_name => value});

       Creates a new ResultSource object.  Not normally called directly by end users.

   column_info_from_storage
       Arguments: 1/0 (default: 0)
       Return value: 1/0

         __PACKAGE__->column_info_from_storage(1);

       Enables the on-demand automatic loading of the above column metadata from storage as necessary.  This
       is *deprecated*, and should not be used.  It will be removed before 1.0.

AUTHORS
       Matt S. Trout <mst@shadowcatsystems.co.uk>

LICENSE
       You may distribute this code under the same terms as Perl itself.



perl v5.12.5                                     2011-07-27                     DBIx::Class::ResultSource(3)